Tubttlak costhectiobr of bridces



UNITED sTATEs PATENT OEEicE.

J. W. SPRAGUE, OF ROCHESTER, NEV YORK.

TUBULAR CONNECTION OF BRIDGES.

Specification of Letters Patent No. 25,852, dated October 18, 1859.

To all whom it may concern:

Be it known that I, JOSEPH WV. SPRAGUE, of Rochester, in the county of Monroe and State of New York, have invented a new and Improved Form of Constructing Iron Bridges; and I do hereby declare that the following is a full and exact description thereof, reference being had to the accompanying drawings and to the lett-ers of reference marked thereon.

Iron bridges as heretofore constructed are attended with serious objections. If cast iron is employed the bridge is liable to break in cold weather from sudden shocks. Bridges made of wrought iron plates require a great many rivets, which weaken the plates at the joints, and are very expensive on account of the labor necessary for riveting. Such bridges require so much metal that the weight is very objectionable. l/Vhen tubular iron has been employed for parts intended to bear a compressive strain, no means have been heretofore found for making an adequate joint between the sections.

My bridge is made chiefly Of boiler plate or wrought iron, and it combines strength and lightness with comparative cheapness of construction.

My invention consists of a series of clutches of peculiar construction, in combination with tubular sections and with braces for making trussed bridges.

In the accompanying drawings, Figure l represents my bridge with the braces removed from the farther side in Order to give a more distinct View of the parts. Fig. 2 is a vertical section through one of the posts and also through the upper and the lower clutch. Fig. 3 is a modified form of the clutch.

In Fig. 1, A, A, are the abutments. The

firmly connected by the clutches O, O. These clutches O have bands c, c, and like the sect-ions B they are tubular. See Fig. 2. The end of the clutch is inserted into the end of the section B, and then the band o is shrunk on, so that the clutch grasps the section both inside and outside and holds it in the most rigid manner. This clutch may be varied in form to suit different positions in the bridge, and yet retain its essential characteristics. The upper chords and the verticals are more fully bound together by braces d, cl. The lower chord G, is made of strong bands of wrought iron, there being a greater number of such bars near the middle of the chord. The girders E, are also made Of tubular iron, in sections, connected by clutches and strengthened by braces t, t, and queen posts s, s. The two upper chords are connected by braces c and F.

It is obvious that the general form of my bridge may be somewhat modified, or some changes in the details may be made under certain circumstances without departing from the essential features of my invention. For example, an additional truss may be employed, or the tubular sections may consist Of tubes placed one within another, (and these concentric tubes strengthened and kept in place by rings of iron,) for the purpose of greater strength in bridges of long spans.

Having thus fully described my invention, what I claim as new in the construction of bridges, and desire to secure by Letters Patent of the United States is:

The above described series of clutches O, provided with bands c, in combination with the tubular sections B, for the purposes subst-antially as set forth.

JOS. W. SPRAGIIE. lVitnesses:

JOSEPH FROST, OYRUs BEARDSLEY. 

